1. Technical Field
The present disclosure relates to a terminal assembly for a vacuum contactor switch which is connected to a terminal of a cradle with electricity applicability to protect a power system by breaking circuits in the event of a dangerous situation such as a short circuit or an overcurrent.
2. Description of the Related Art
Typically, the vacuum contactor switch (VCS), which is an industrial device for turning on/off high-voltage-related electric devices such as a high-voltage motor, a transformer and a condenser, is designed to withstand the frequent opening and closing operation with a capability of allowing application of a high-voltage rated current.
Specifically, the VCS mainly functions to control opening and closing of an electric circuit. The VCS is used to protect and control loads such as a motor by operating/stopping the loads. The operation of the VCS is selectively performed by operation of an electromagnet.
The VCSs may be divided into fixed VCSs configured with a breaker body alone and fixedly installed on a distribution board panel and withdrawable VCSs provided with a cabinet called a cradle for facilitating maintenance of the contactor switch and configured to allow the breaker body to be inserted into/withdrawn from the cradle.
FIG. 1 is a diagram illustrating a withdrawable VCS according to the prior art. Hereinafter, a description will be given of current flow formed with a breaker body 1 coupled to a cradle 2.
First, a current applied through an insertion bus bar 10 enters into a main circuit part 40 via a bushing terminal 20 and a contactor 31 and body portion 32 of an upper terminal assembly 30. The current having entered into the main circuit part 40 flows to a load-side withdrawal bus bar 70, passing through a body portion 52 and contactor 51 of a lower terminal assembly 50 and a bushing terminal 60 via a vacuum interrupter in the main circuit part 40.
That is, when the body portions 32 and 52 of the terminal assemblies 30 and 50 move back and forth while being inserted and fixed in terminal holes 80 of the cradle 2, the current is applied to the load side or interrupted according to connection/disconnection of the contactors 31 and 51 to/from the bushing terminals 20 and 60.
However, in the case of the conventional VCS, since the diameters of the terminal holes are divided into 29 mm and 35 mm according to the type of the cradle, it is required to use a terminal assembly having a different diameter according to the size of the terminal holes.
Therefore, change in the diameter of the terminal hole requires employment and installation of a corresponding terminal assembly, and accordingly it is difficult to manage the components. Further, terminal assemblies having a diameter of 29 mm and a diameter of 35 mm need be manufactured, respectively, which results in increase in the manufacturing cost.